DIYARBAKIR, Turkey (Reuters) - One soldier was killed and three police officers were wounded in a clash with Kurdish militants in southeastern Turkey on Monday, security sources said, as a spike in violence rocks the restive region.

A suicide bomber, as young as 12, late on Saturday blew him or herself up at a wedding party in the city of Gaziantep, killing 51 ethnic Kurds in an attack President Tayyip Erdogan said was carried out by Islamic State.

That attack was the deadliest in a series of bombings in Turkey this year blamed on Islamic State and their rivals, the Kurdistan Workers Party (PKK), an outlawed militant group seeking greater autonomy for Turkey's 15 million Kurds.

NATO member Turkey is also roiling with the aftermath of a failed coup on July 15 that killed an estimated 340 people, including around 100 of the rogue soldiers.

A female PKK guerrilla was also killed in the clash, which erupted at dawn near security outposts by the town of Nazimiye in Tunceli province, 500 km (310 miles) northeast of Gaziantep, the security sources said.

Authorities imposed a round-the-clock curfew on Nazimiye as security forces, backed by attack helicopters, sealed the area and sent in reinforcements, they said.

On Sunday, the PKK targeted a military vehicle in Viransehir in Sanliurfa province, killing one soldier and wounding four, security sources said. The PKK took responsibility for a car bomb attack on Thursday the in eastern city of Elazig, killing three and wounding hundreds.

The PKK took up arms against the Turkish state in 1984, and more than 40,000 people, mainly Kurds, have died. It has close ties to the Syrian Kurdish YPG, which is battling Islamic State in northern Syria and is backed by the United States, a Turkey ally.